The present invention relates to an assembly consisting of a frame element of a motor vehicle, a connecting element and a component fastened to the connecting element. In particular, the invention also relates to a chassis of a motor vehicle which includes such an assembly.
In the automotive industry, or in the manufacture of motor vehicles, various portions of the motor vehicle are made from appropriate frame structures. An example of such a frame construction is the chassis of a motor vehicle shown in FIG. 8. The corresponding frame construction is formed by means of various frame elements ST2, ST3 which are connected to one another. In order to attach the wheel suspensions, for example, connecting elements ST4 are provided on the frame structure at certain points, to which connecting elements there can be fastened corresponding links of the wheel suspension and/or struts. In order to fasten the links or struts, use is often made of rubber bearings so that compressive or tensile loading can be absorbed to a certain degree.
The use of such rubber bearings increases the weight on the one hand and leads to an increase in the parts making up the chassis on the other hand.
Against this background, it is an object of the present invention to provide an assembly which leads to a weight reduction and simplification of the assembly.
This object is achieved by an assembly which includes a frame element of a motor vehicle; a connecting element which is fastened to the frame element; and a component which is fastened to the connecting element; wherein an integrally bonded connection, which is provided between the connecting element and the frame element, and/or the connecting element are/is formed in such a way that they have a modulus of elasticity which is less than a modulus of elasticity of the component.
Further preferred embodiments of the assembly according to the invention are described and claimed herein.
According to the invention, the assembly includes a frame element of a motor vehicle and a connecting element which is fastened to the frame element. A component is, in turn, fastened to the connecting element.
An integrally bonded connection, which is present between the frame element and the connecting element, and/or the connecting element of the assembly according to the invention, are/is formed such that the integrally bonded connection and/or the connecting element have/has a modulus of elasticity which is less than a modulus of elasticity of the component.
This configuration of the integrally bonded connection and/or of the connecting element means that they have an elastic property that effectively assumes the function of an elastomer bearing, for example a rubber bearing. In other words, the integrally bonded connection and/or the connecting element are formed such that they are more elastic than the component fastened to the connecting element and, in this respect, when an intended force is introduced into the frame element via the component and the connecting element, there occurs a greater elastic deformation of the integrally bonded connection and/or of the connecting element than of the component.
This configuration according to the invention of the assembly means that it is not necessary to provide a separate elastomer bearing, for which reason there results a weight reduction, a simplification of the entire assembly and a reduction in the number of parts.
The frame element of the motor vehicle can be formed from metal or a fiber-reinforced plastic, it being possible for the frame element to have a cross section which is tubular or else formed differently.
The fibers reinforcing the frame element can be short fibers (0.1 to 1 mm), long fibers (1 to 50 mm) or endless fibers (>50 mm).
The integrally bonded connection can be produced, for example, by an adhesive. A variety of adhesives can be used in dependence on the intended loading of the assembly according to the invention or on the magnitude of the forces which act as intended. Examples thereof are very high-modulus adhesives with a modulus of elasticity >800 MPa, high-modulus adhesives with a modulus of elasticity of 100 to 800 MPa and also low-modulus elastic adhesives with a modulus of elasticity of <100 MPa.
In addition, the adhesive can be cold- or warm-curing.
The connecting element can also be configured differently with respect to geometry and material in dependence on the intended loading. Materially, the connecting element can be formed, for example, from a metal, a fiber-reinforced plastic (fiber lengths as explained in respect of the frame element), a stiff adhesive and also from an elastomer.
By combining the above-explained configuration of the integrally bonded connection and of the connecting element, a necessary elasticity for the intended loading and the intended use of the assembly can be achieved.
Preferred configurations are:
1) connecting element made of elastomer with a certain modulus of elasticity (to assume the elastic function) with/without the envelope explained in more detail below, the fastening of the connecting element to the frame element being arbitrary;
2) the combination of connecting element made of metal/fiber-reinforced plastic and integrally bonded connection with a certain modulus of elasticity (to assume the elastic function); and
3) connecting element made of an elastomer with a certain modulus of elasticity (to assume the elastic function), which itself functions as an adhesive and via which the connecting element is fastened to the frame element, with/without the envelope.
The connecting element can be configured differently in dependence on the intended use of the assembly. If the connecting element is, for example, a connecting element provided for fastening a link of a wheel suspension, it can have one or two attachment portions to which the link of the wheel suspension can be fastened via a screw connection. The attachment portions can be individual parts or provided together on a bearing portion which is brought into bearing contact with the frame element. Should the attachment portions each be individual parts, they can also have a laterally extending bearing portion.
Moreover, the connecting element can also be configured such that the attachment portions have a counter-holder by which they together enclose the frame element.
The integrally bonded connection is produced via the adhesive between the connecting element and the frame element.
According to the invention, the integrally bonded connection and/or the connecting element are/is geometrically formed in such a way that the integrally bonded connection and/or the connecting element have/has a force-extension characteristic of an elastomer bearing. The force-extension characteristic is, in particular, a conventional force-displacement characteristic.
As a result, the behavior of an elastomer bearing, such as, for example, a rubber bearing, can be readily integrated into the assembly.
According to the invention, the connecting element can be formed from an elastomer. In this case, the connecting element can be indirectly fastened to the frame element via the integrally bonded connection or an adhesive. If the elastomer itself functions as an adhesive, the connecting element can be most readily directly fastened to the frame element.
In a preferred configuration of the assembly according to the invention, the integrally bonded connection is formed from a low-modulus adhesive which has, in particular, a modulus of elasticity which is less than 100 MPa.
Such an adhesive is particularly suitable for use in the field of chassis construction since the properties of an elastomer bearing can be readily reproduced thereby.
According to a further preferred configuration of the assembly according to the invention, the connecting element is formed from an elastomer and surrounded by an envelope which has a modulus of elasticity which is greater than the modulus of elasticity of the elastomer. The envelope is preferably formed from an upper and lower shell.
This configuration according to the invention makes it possible to ensure that the connecting element behaves differently in dependence on tensile and compressive loading. In particular, in the case of tensile loading, the connection between the frame element and the connecting element is supported in such a way that the risk of tear-off of the connection is reduced.
According to a further preferred assembly of the invention, the integrally bonded connection is formed from an adhesive and the connecting element is formed from a metal, wherein an adhesive layer formed from the adhesive and situated between the frame element and the connecting element has a thickness of up to 10 mm, in particular between 1 mm and 10 mm.
By forming the connecting element from metal it can be ensured that the component is readily fastened to the connecting element. In this preferred configuration of the assembly according to the invention, the adhesive layer, which has a thickness of up to 10 mm, assumes the function of the elastomer bearing.
In a further preferred configuration of the assembly according to the invention, the connecting element is formed from an elastomer and has a through-opening at which the component can be fastened via a screw connection, wherein a reinforcing ring is inserted into the through-opening. Whereas the connecting element made of the elastomer assumes the function of the elastomer bearing, it is possible to achieve ready fastening of the component to the connecting element via the reinforcing ring.
In a further preferred configuration of the assembly according to the invention, in addition to the integrally bonded connection, the connecting element is fastened to the frame element by a fiber winding.
The fiber winding can be formed, for example, by a carbon fiber, glass fiber, aramid fiber or natural fiber. Moreover, the fiber winding can be formed by an individual fiber or else by a plurality of fibers.
Moreover, the fiber winding can be embedded in a plastic matrix consisting of a thermoset or thermoplastic.
Moreover, the fiber winding can be formed such that the fiber forming the fiber winding is wound around the frame element and the connecting element in such a way that fiber portions on the surface of the frame element or of the connecting element extend parallel to one another or else cross over one another.
Generally, the fiber winding can be produced in such a way that the fiber forming the fiber winding extends perpendicularly to a longitudinal direction of the frame element. If the fiber winding is built up from a plurality of individual fibers, it is also possible for the individual fibers to cross one another. In other words, the fiber(s) can form geodetic lines which connect points which lie at the same height with respect to the longitudinal direction or are offset from one another.
The surface on which the fiber winding extends can have concave portions, for example grooves, to secure and position the fiber winding.
In the case that the connecting element is enclosed by the above-explained envelope, this envelope ensures that there is no risk of the fiber winding being released on account of the elastic movement of the connecting element or of the integrally bonded connection.
In a further preferred configuration of the assembly according to the invention, the integrally bonded connection is formed from an adhesive and the frame element extends in a longitudinal direction. An adhesive layer formed from the adhesive and situated between the frame element and the connecting element is preferably formed in such a way that a quantity of the adhesive increases at end portions of the connecting element which are situated in the longitudinal direction.
For example, the connecting element is configured such that a gap between the frame element and the connecting element in which the adhesive is situated becomes larger at the end portions of the connecting element which are situated in the longitudinal direction. This can be achieved by virtue of the connecting element having on the bearing surface, by which it bears against the frame element, tapering and/or else stepped—preferably multiply stepped—end portions.
Furthermore, for example, an excess of the adhesive can be applied in such a way that a bead is created at the end portions.
The invention also relates to a chassis of a motor vehicle, wherein the chassis includes an assembly in accordance with the above explanation.
All the explanations given above, in particular with respect to the modulus of elasticity, materials of the frame element and connecting element, and the fiber winding correspondingly apply to the following embodiments.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.